BEAD FORMING METHOD AND STRUCTURAL MEMBER

A bead forming method includes the steps of preparing a bumper stay having a partition wall that partitions an internal space and extends in a longitudinal direction, an elastic body that can be inserted into the bumper stay, and a pusher that presses the elastic body; inserting the elastic body into the bumper stay and arranging the elastic body in the bumper stay so as not to come into contact with the partition wall; and forming a buckling bead by compressing the elastic body in the longitudinal direction of the bumper stay by the pusher to expand the elastic body outward in a radial direction without coming into contact with the partition wall, thereby bulging a part of an outer wall of the bumper stay outward in the radial direction without deforming the partition wall.